Cervical skeleton traction is used exclusively to treat the unstable spine. It is also sometimes used in treating signal fractures and to accomplish reduction of cervical facet dislocations. In the past, skeleton traction has been applied utilizing caliper-like devices and halo-type rings. Both types of devices use pins which are drilled or screwed through the scalp into the skull to allow force vectors to be applied to the skull and spinal structure.
Exemplary of the caliper devices of the prior art are the Crutchfield Tongs. This device was in the shape of an "X" and was pivoted at the intersection of the two arms. At the scalp end of each arm, a pin was affixed for penetration into pre-drilled skull holes. At the other end of each arm, there was a threaded rod and thumb screw structure which, when operated, tended to force the pin ends of the tong arms together or apart in accordance with the direction in which the thumb screw was turned. These tongs were applied to the top of the head with one pin on each side of the longitudinal axis of the spine. The pins were roughly perpendicular to the scalp, but because the tongs did not reach down around the head to a point just above the ears, the angle of the scalp pins to the longitudinal axis of the spine was acute when viewed from the front or rear of the head. Accordingly, when tension was placed upon the Crutchfield Tongs, the angle of the pins was such that, if not tightly compressed by the thumb screw, it was possible to pull the Crutchfield Tongs completely out of the skull.
Only two pins were used in the Crutchfield Tongs. As a result, a pivot line was established between the contact points of the pivot points and the skull. Thus, flexion and extension of the skull in relation to the spine, i.e., tilting of the head forward and rearward, was not possible with the Crutchfield Tongs. Further, traction using the Crutchfield Tongs confined the patient to bed such that ambulation was not possible.
Another example of caliper devices are Barton's tongs. The structure of Barton's tongs was similar to that of the Crutchfield device; however, the arms are longer such that the pins reach further down on the head toward the ear. The shape and length of the tong arms was such that the drills of Barton's tongs entered the skull horizontally at a point somewhere between the top of the head and the ear, such that a 90.degree. angle was formed with the longitudinal axis of the spine. Barton's tongs had a greater resistance to pulling out of the skull than did Crutchfield's tongs, because of the increased angles of the pins with respect to the spine.
Another example of this type of device is the Gardner tongs which had a different structure than the Crutchfield tongs and were less likely to loosen under prolonged traction load than were Crutchfield's tongs. Gardner's tongs were a semicircular frame structure in the approximate shape of a horseshoe with threaded pin holes on each end of the horeshoe arms. The horseshoe was placed down over the patient's head such that the pins contacted the skull at a point just above the ears and in line with the longitudinal axis of the spine. Thus the plane defined by the two pins and the point of contact of the tongs with the traction line passed through the center line of the spine. Excessive anterior placement of the tongs resulted in a forward tilt of the head resulting in misalignment of the spine. Since only two pins were used, a pivot line was formed and it was not possible to apply flexion and extension force vectors in the anterior-posterior plane with this device.
Anterior-posterior positioning of pins was disclosed in Russian Pat. No. 633,526. That patent discloses a tong-like device with facility for affixing two pins on either side of the head. This patent also discloses a plurality of holes centered at the top of the horseshoe and spaced about its center line. This feature plus the four points of contact with the skull allowed the skull to be canted from left to right by placing the hook of a traction line to the left or right of the centerline of the horseshoe.
The inconvenience and attendant additional risk of confining a patient to bed during extended traction resulted in the development of the halo-type device. The halo device consisted of a circular frame with an upturned portion in the rear, said frame completely encircling the skull. Several pins were used to engage the skull, resulting in increased ability to control the force vectors of the traction force. Force was applied to the halo ring by means of two hooks which attached to the halo ring on either side of the head in line with the longitudinal axis of the spine. These hooks could be moved forward or rearward to control flexion and extension torques on the skull in the anterior-posterior plane. Further, the halo could be attached to a plaster body cast or a vest type structure with supporting linkage to allow traction to continue while the patient ambulated. This mobility was the principal advantage of the halo ring, although another advantage existed in that there was no movement between the skull and fixation pins. This reduces the chance of infection of the scalp in the areas surrounding the pins.
Because the halo completely encircled the head, it was necessary during application that an assistant gently lift the head from the stretcher or support the head off the end of the table to provide sufficient space for the ring to be positioned around the patient's head.
Generally, the halo ring was placed just above the external ear. Pins were inserted through threaded holes spaced around the ring and diagonally opposite pins were tightened simultaneously using torque screwdrivers. The pins were then locked into place with set screws.
A disadvantage of the halo was that x-ray films of the pin location in the skull were difficult and deceptive, unless the x-ray was made of each pin at an angle tangential to the skull at the point of entry of the pin. The halo type ring also generally left pin hole scars over the eyebrows because the anterior placement of the pins was generally in the forehead region.